We observed chromosome-banding abnormalities in leukemic cells of 46 of 90 (51 per cent) adults with acute nonlymphocytic leukemia at initial hospital admission. The difference in survival between 37 treated patients with an initially normal karyotype (10 months) and 43 with an initially abnormal karyotype (four months) was significant (P less than 0.01). When patients were classified as having acute myelogenous leukemia or acute myelomonocytic leukemia, this difference in survival was even more pronounced. Of 16 treated patients with acute myelogenous leukemia and a normal karyotype, 11 (69 per cent) had a complete remission and a median survival of 13 months. Of eight patients with acute myelogenous leukemia in whom only abnormal metaphases were observed, none had a complete remission, and the median survival was only two months (P approximately 0.50). Remission rate and median survival were not significantly different in patients with acute myelomonocytic leukemia grouped according to initial karyotypes.
